Seadrome



Dec. 127, 1932. E. R. ARMSTRONG S EADROME 8 Sheets-Sheet 1 Filed June 8. 9

Dec. 27, 1932. E. R. ARMSTRONG ,3

'SEADROME FiledJune 18, 1930 8 Sheet's-Sheet 3 wzww Dec. 27, R ARMSTRONG 1,892,125-

S EADROME Filed June 18, 1930 8 Sheets-Sheet 5 Dec. 27, 1932.

E. R. ARMSTRONG SEADROME Filed June 18, 1930 8 Sheets-Sheet 8 Patented Dec. 27, 1932 1 EDWARD R. ARMSTRONG, OF HOLLYOAK, DELAWARE SEADROME Application filed June 18,

This invention relates to certain improvements in sea stations and more particularly concerns the construction and arrangement of such stations by which they may be more easily constructed and rendered more stable in service.

By my prior U. S. Letters Patent No. 1,511,153, granted Oct. 7 1924, I have (llS- closed a sea station for employment as a seadrome for permitting the alighting of airships upon a plane surface during transoceanic flight. The present invention proposes certain modifications and improvements therein.

One of the objects of the present invention is to provide an assembly for a sea station which may be constructed and its parts connected in shallow and protected Waters, and the entire station then towed to its intended permanent position and anchored thereat, and its parts then brought into such relationship to one another as to permit'the maintenance of the station without substantial deviation from position and in stable equilibrium and at a substantially uniform level.

Another object of this invention is to provide a floatation system for the supporting of the alighting surface proper by which each individual supporting element is substantially self-sustaining and delivers at all timesa substantially uniform lifting and'supporting effort with respect to the alighting plane, regardless of the conditions of the sea with respect to height or length of waves.

A further object of the invention is to provide a mooring system for such a sea station which will prevent fouling.

Still another object of the invention is to provide improvements in the details of construction and assemblage of the parts.

With these and other objects in view, an i lustrative form of sea station according to this invention has been set forth on the accompanying drawings, in which:

Fig. 1 is a diagrammatic horizontal section, showing arrangement of units;

Fig. 2 is a side elevation, with the ballast tanks in lowered position Fig. 3 is a rear elevation;

Fig. 4 is an enlarged vertical section of the 1930. Serial No. 462,046.

upper portion of the buoyancy section of one buoyancy or supporting unit, at its attachment to the superstructure;

Fig. 4a is a similar section of the lower portion of such abuoyancy section, showing the connection to the supporting column of the ballast section;

Fig. 4b is a similar vertical section of the ballast portion of one unit;

Fig. 5 is a horizontal section on line 5-5 of Fig. 4;

Fig. 6 is a horizontal section on line 6-6 of Fig. 4a;

Fig. 6a is a horizontal section on line 6a6a of Fig. 4a;

Fig. 7 is a horizontal section on line 77 of Fig. 4b;

Fig. 8 is a detailed view, on a yet larger scale, of the connection between a ballast column and a buoyancy section;

Fig. 9 is a side elevation of the front of station, on a larger scale than in Fig. 1, showing mooring elements;

Fig. 10 is a horizontal section of same, substantially on line 10-10 in Fig. 9;

Fig. 11 is a. diagrammatic perspective view of the winding gear;

12 is a fragmentary horizontal section on line 12-l2 of Fig. 3, showing the air rudder;

Fig. 13 is a circuit diagram of air rudder controlling devices. A

A sea station of the present type is intended to be secured by permanent anchors at a distance from land, and therefore is exposed to all weather conditions of wind and waves which exist at sea. Winds occurs of various velocities, which give rise to movements of the surface of the ocean known as waves. These waves are characterized by a fairly well defined length from crest to crest with respect to their depth from crest to trough. Many theories have been proposed and discussed with respect to the mathematical relationships of these wave dimensions. None of the presently proposed theories is accurate in all instances and gives predictable results for the lengths and depths of all waves, for the crest angle of waves, and for the depth to which the ocean is disturbed by particular waves.

However, the so-called trochoidal wave theory defines many of the factors so accuratel that it is generally accepted as stating the enomena occurring in waves.

liilder this trochoidal wave theory, it is assumed that the ocean is uniform in density, is continuous, and the particles are irrotational, and further that the wind velocity does not cause a breaking or blowing of foam from the ridge of the crest. If these conditions are not present, slight corrections occur but it has been found that these corrections do not substantially modify the principal theory, and in particular that they are of such small amount in practice that a structure according to the present invention can be considered as operating with the waves developed according to the strict trochoidal theory. Under the trochoidal theory, again, each particle of water is assumed to be moving in a circular path. The diameters of these paths decrease successively downward from the crest of the wave. The crest of the wave is therefore momentarily produced by particles of water which constitute the surface layer and" which have reached the uppermost part of their circles of movement, these circles eing the uppermost of a series. Each particle at the water surface may also be considered as being the uppermost particle in a vertical column of particles extending downward to the ocean floor. Each succeeding lower particle moves in a circular orbit of slightly lesser diameter than the particle above it. Owing to the retarding causes such as molecular cohesion and surface tension, a

particular wave produces noticeable orbital movements of water particles for only a certain defined distance downward from the normal water level, i. e., the level at which the bcean would exist were there no waves or even ripples. This distance, however, is so great that it would not be practicable to provide sea anchors or supporting structures for sea stations of the present nature which would be immersed to this depth. For example, with a wave as produced by a wind of 40 knots per hour, the disturbance may extend to a noticeable degree for several hundred feet in depth.

As each particle at the crest of the wave begins its downward movement in its orbit, a succeeding particle in the adjacent vertical column is reaching the top of its movement and thus is constituting the new wave crest, and so on in succession as the wave travels.

It will thus be noted that there are many factors acting upon the particles of water,the princi al of these being: (1) gravity; (2) centri uga-l eflects on the particle as it moves in 1ts orblt; (3) wind pressure; (4). surface tension; (5) viscosity. The latter two are relatively unimportant in their effects even with small waves: and it will be understood that the size of the supporting structures aceeann cording to the present invention are such that the efiectsofsmall waves of a few feet in length from crest to crest are to be discounted. However, as a. particle moves in its orbit the centrifugal effects tend to throw the particle of water away from the center of the orbit, so that when the particle reaches the top of the orbit it tends to be projected vertically upward by a force which may be calculated as a function of the weight and speed of the article and the diameter of its orbit. This is opposed by the gravitational pull downwardly: but at the particular instant, the water particle has an upward component of force counteracting the pull of gravity, and hence the pressure or density of the water at the crest is less than the normal density of water at a standstill and at the same distance from the surface. Likewise, in the trough, the water particle has reached the downward limit of its travel, and centrifugal force new acts upon it to push it downwardly, assisting gravitation in this instance: and hence the pressure or density of the water at the trough of the wave is greater than the normal pressure or density of water at a. standstill and at the same distance from the surface.

According to the present invention advantage is taken of the fact that this difierence of apparent water pressure or density exists at the troughs and crests of waves, to secure a substantially uniform lifting eifort upon each of the sustaining units of the sea station.

The wind force acting upon the particles of water give rise to the breaking of the crest or the so-called blowing of spume and also to a regular progressional movement of the water withthe wind. Not only is the size of an ocean wave as to relative length from crest to crest or depth from crest to trough determinable under the trochoidal theory, but also the actual speed of movement of the crest, since obviously this is a function of the diameter of orbit and speed of movement of a particle in its orbit. This orbit, under the trochoidal theory, is to be regarded as the rolling circle developing the trochoid of the wave at the particular depth. Thus the orbital circles of greater diameter determine the trochoidal shape of the wave surface, while the successively smaller lower orbital circles determine trochoidal surfaces which enable the calculation and testing of water pressures at different depths.

In the drawings, the sea station is shown as having the alighting surface or deck 10 comprising the central main alighting floor and lateral extensions therefrom which maybe provided with deck structuresll for the storage of airplanes and supplies, service and operating quarters and repair shops, etc. Extending downwardly from the deck 10 are a plurality of tubular supporting members 12 which are stream-lined to avoid weather and water resistance. It will be understood that the sea station is secured by a cable 3 to a mooring buoy 4 which in turn has an anchor cable 4a passing to an anchor on the ocean floor, thus serving to cause the sea station 5 to present its front end a to the wind at all times, and maintain the sea station substantially at a predetermine spot. It will be noted that the columns 12, lateral structures 11 and other parts are stream-lined to 10 receive winds from this direction. The columns are spaced apart laterally and lengthwise of the sea station by spars 34 (Figs. 1, 2, 3, and 5). The tubular supporting members 12 have the stream-lined outer walls above referred to, and internal bulkhead walls 13 which are continued downwardly through the buoyancy tanks secured at the lower ends of the columns 12: a central portion 12a of the outer wall of each member is likewise continued downward in the respective buoyancy tank on two sides thereof.

Each of the buoyancy tanks has the cylindrical outer Wall 14, the upper closing wall 15, intermediate horizontal floor plates 17 17a, the bottom wall 16, and the vertical radial bulkheads 39 which extend from the upper wall 15 to the intermediate floor plate 17 a, in the illustrated example of construction. These bulkhead walls are aligned longitudinally and transversely of the sea station, in this example. Bracing rings and irons 12b and 14?) are provided respectively within the column 12 itself and within the buoyancy tank 14 to stiffen and reinforce these structures against the pressure of the water while quiescent and while moving. The walls and bulkheads 12a, 13 preferably terminate at the intermediate floor plate 17a, and likewise the radial bulkheads 39, so that the chambers be- 0 tween the upper Wall 15 and the floor plate 17,

and between the floor plates 17, 17 a are divided into a plurality of independent compartments; while the space between the floor plate 17 a and the bottom wall 16 is open.

The floor plate 17a closes the bottom end of the well within the walls and bulkheads 12a, 13 except for an aperture within the cylindrical well wall 18 (Fig. 4a) which extends between the floor plate 17 and the bottom plate 16 and receives in guided relationship the connecting column 19. which may thus telescope upwardly into the well formed by the walls and bulkheads 12a, 13. The column 19 is preferably formed with double walls (Figs. 4a, 4b and 8) the outer wall being guided by the well wall or sleeve 18. The upper end of the outer wall of the column 19 is provided at its top with a packing 19p held in position by a clamping angle iron 198 which in the lowered or extended position of the column 19 rests against the floor plate 17 a, and may be secured thereto by bolts 19m. The space between the double walls of the column 19 is preferably provided with bracing irons 197:: (Fig. 7) for 6 greater strength. The upper end of the column 19 is closed by a plate 20 having a closable man-hole 20m therein.

At the lower end of the column 19 is provided a ballast chamber having the top wall 21, the cylindrical peripheral wall 22 and the bottom wa1l23, which are sealed and radially connected at the lower end of the column 19, suitable internal bracing, as indicated at 24 (Fig. 46), being provided for the structure. The well located within the hollow column 19 is closed at the bottom by a plate 25 having a sea valve 26. A damping disk 27 extends around the ballast tank, and is connected thereto by braces 27a.

Each of these columns 12 with its connecting column 19 and associated parts, including the buoyancy and ballast tanks, constitutes a supporting unit for the deck structures; and

each of these units operates substantially independently of the others to maintain its predetermined proportion of the total weight.

The various units are connected together by girders and beams G (Fig. 4) supporting the deck 10, the design of the units being such that each has a substantially constant buoyant or supporting capacity, irrespective of wave action, so that the girders and beams G are maintained substantially free from twisting or bending strains.

In Fig. 4 the upper end of the well formed by the walls and bulkheads 12a, 13 is closed by a plate 30 having a man-hole and cover 30m therein by which access may be gained to the well itself. The well, however, is otherwise hermetically sealed so that when the man-hole cover 30m is in position, air may be blown into the well through the pipe 31, or let out of the same, as will be described more in detail hereinafter. It is preferred to connect all of the air pipes 31 with mains 31a (Fig. 1) and thus with the air compressor system 32 which controls the air pressure, so that by control of the air compressors 32, and of the escape valves 33, the air pressure within the wells may be regulated simultaneously for all wells by pumping in more air, or by permitting air to escape therefrom. Thus, the buoyancy of the various units may be regulated together whereby to cause the station to ride relatively higher or lower in the water for reasons which will be pointed out hereinafter. In Fig. 1 the air compressor installations 32 are shown as three in number, and as being diagrammatically connected with the mains 31a and thence with the branch pipes 31 leading to the connecting columns 12 and their wells. It is preferred to provide a. plurality of separate compressors 32, owing to the size of the sea station, and to join these compressors to relatively short air mains 310 leading to the branch pipes 31: these compressors being operated and controlled by a common system. This arrangement reduces losses by air friction in the pipe lines and makes possible an immediate and eflective control of the functioning of the station as a whole. Individual cut-off and control valves 316 (Fig. 4) are provided on the branch pipes 31 for controlling the admisslon of 5 compressed air, and the escape of air to atmosphere with respect to the individual units, so that the units may be handled independently in the event of damage or leakage, and when it is desired to inspect or repair them. In particular, it will be noted that the air compressor plants 32 (Fig. 1) are located adjacent the catwalks K which are located beneath the deck 10, preferably being supported by the lower girders G of the deck construction: these catwalks lead to various parts of the sea station so that attendants and others can pass from one side or end of the deck to another point without traversing tllie rlpain deck surface upon which the planes a ig t.

Beneath the beams and girders 'G (Fig. 4) of the deck construction, the units are joined one with another by the connections 34 which maintain the units in their spaced relationship with respect to one another. Furthermore, cables 36 are employed as diagonal braces (Figs. 1, 2, 3, 4, 4a and 6) for the supporting units. In the upper end of the columns 12, these are provided with the plates 35 to receive the upper ends of the brace cables 36 which are preferably provided two in parallel with one. another (Fig. 6), and which pass through the sleeves 37 secured in the walls 14 of the buoyancy tanks. From the inner ends of these sleeves 37 the brace cables are led to the junction plates 38 which are rigidly secured to the adjacent floor 17 to the bulkheads and walls 12a, 13 and also to radial bulkhead plates 39 located within the particular compartment. Of the two cables, one is located at each side of the wall 39, so that the entire strain is transmitted to this bulkhead wall and thus to the buoyancy tank, being distributed both to the inner walls or bulkheads 12a, 13 and to the outer peripheral wall 14, as well as to the several floors 17 and the end plates 15, 16. A packing 40-is provided at the inner end of the tube 37, and it is preferred to stream-line the tubes on the exterior of the buoyancy tanks and to fill the space between the tubes and the cables with water-proofing compound. Access may be gained through the man-hole door 30m and through normally closed manhole doors 41 into the respective compartments for the purpose of tightening the holding nuts 42 at the lower ends of these brace cables. The sleeves 37 extend upward well above the water line, and terminate close to the wall of the respective column 12.

The buoyancy unit illustrated in Fig. 4a has a closing plate 150 extending within the hollow column 19 to close it, being provided with a man-hole and man-hole cover 151 by 65 which it is possible for an attendant to enter the column 19 past the man-hole cover 20m and the cover 151, even when the column 19 is extended if appropriate air pressure has been developed within the well formed by the walls and bulkheads 12a, 13 and/ or the space between the plates 20, 150. This closing plate 150 is provided with a sea valve 152 operable by a rod 153 passing upwardly through the plate 20 and provided with a handle at its upper end, being suitably packed with respect to the plate 20. The sea valve 26 (Fig. 4b) is likewise provided with a rod 154a extending upwardly through the plates 150, 20, being packed with respect to each, and is likewise provided with a handle at its upper end. Thus, it is possible for an attendant standing upon the plate 20 to open or close either or both of the sea valves 26, 152. A pipe 154 opens into the space between the plates 150, 20 near the bottom thereof, and extends upwardly and through the upper closing plate 30, so that the space between the plates 20, 150 may be employed as a storage tank for fuel, for example, and the fuel forced therefrom by air pressure and delivered through the pipe 154.

The individual branch air pipe 31 passes through the top closing wall 30 (Fig. 4) and is provided immediately therebeneath with a valve 155 by which the air may be admitted directly into the well formed by the walls and bulkheads 12a, 13. A branch pipe 156 extends downwardly in this well, outside of the path of the column 19 in its telescoping movement, and terminates adjacent the lower end of this wall, being provided with a valve 157 accessible to an attendant at the bottom of the well. A flexible hose 158 connects the lowel end of this pipe with a nipple or similar outlet on,the plate 20, so that compressed air from the pipe line 31 may be forced into the tank between the plates 20 and 150. Thus, when the column 19 is in its upper position, and the flexible hose 158 has not yet been attached, it is possible to pump air through the pipe 31 and force the column downward by air pressure: or the sea valve 26 may be opened to permit water to enter, so that the column will fall by gravity as well, being controlled in its descent by the air cushion behind it, this cushion being regulated by the operation of the valve 316 so that the rate of descent is controlled. Further, if no fuel or other liquid supplies are in the tank between the plates 20, 150, it is possible by open ing the sea valves 26, 152 and controlling the valve 157, to force water from the internal space of the hollow column 19 whereby to adjust the buoyancy of the particular unit.

The various compartments separated by the radial partitions 39 are provided with drains leading into the bottom compartment between the intermediate floor plate 17 a and the bottom wall 16. The pipes 160 lead from respective compartments and are individual- 1y controllable by the valves 161, by an attendant in the well formed by the walls and bulkheads 12a, 13. Similarly, the short pipe connections 162 are provided with valves 163 controlled by handles extending through the packed tubes 164, so that these valves may be opened or closed by the attendant. A suction pipe 165 from the bottom of the lower compartment leads to a pump 166 having a drivmg motor 167 so that water within this compartment may be forced outward through the pipe 168 and delivered (Fig. 4) through the outlet 169 back to the ocean. In this way, it is possible to regulate the quantity of water contained in any compartment of the buoyancy tank for controlling the buoyancy, metacentric stability, etc., as may be desired.

A sea valve 170 is located in the floor l6 and is operable by a valve rod 171 which'extends upwardly through the plates 17a, 17, the top wall 15 and through the front section of the connecting column 12, and teiminates in a handle 172 (Fig. 4) which can be operated by an attendant at deck height. Thus, it is possible to permit Water to enter the lower compartment; or by the employment of air from the pipe 31, to force water out of this compartment, by opening the valve 179 to admit air from the pipe 31 into pipe 178 and thus into the buoyancy tank chamber between the bottom wall 16 and the floor 17a (Figs. 4 and 4a).

In the ballast tank, it is preferred to employ an air balancing conduit 175 through the walls of the connecting column 19 and through the inner wall 22a of the tank, so that air pressure may balance itself within the annular ballast chamber. Similarly, a water conduit 176 is provided near the bottom of this compartment. Thus, if the sea valve 26 is Opened, water can enter at the bottom of the hollow column 19, and fill this column and also the annular ballast compartment to a level determined by'the air pressure existing in the column 19: and further, if a greater air pressure is developed, water may be forced out of the sea valve 26 again, and even out of the ballast chamber, if the pressure be sufficient.

As indicated above, the connecting column 19 may be telescoped into the well formed by the walls and bulkheads 12a, 13, and gripping hooks 180 are provided to engage the upper flange or angle iron 19s of the connecting column to hold it mechanically in such position. This holding relationship is further assisted by closing the sea valve 26, and the air valve 316.

It will be understood that each of the columns is constructed in the same general manner. Itmay be pointed out that the total length of a sea station of this type may be 1100 feet, and its over-all width 340 feet: the depth from the deck to the bottom of the ballast support tanks while the latter are in lowered position may be 240 feet, with a depth from the'water line to the bottom of the ballast tank of the order of 160 feet. The outer supportin units, of which five are illustrated as provi ed beneath each of the lateral extensions, may have the buoyancy tanks 34 feet in diameter by 38 feet in depth, while the connecting columns 19 thereof have a diameter of 10 feet. The inner supporting units correspondingly may have a diameter of 27 feet with the same depth of 38 feet, while the connecting columns 19 of the same are 8 feet in diameter. The outer lateral columns are larger in order to give a relatively high righting movement against rolling as a result of a sudden shifting of the wind,

before the station as a whole has had time to travel around its anchor.

Obviously, a structure of such a size and depth could not be assembled in shallow water, but it will be noted that by constructing the station with the connecting columns 19 wholly withdrawn within the chambers formed by the bulkheads 12a, 13 (as shown in dotted lines at the left of Fig. 2), the total draft may be reduced to 32 feet. The sea station may thus be assembled in a relatively shallow basin of sufiicient size, and then towed to its permanent location. It will particularly be noted that no parts connecting the several units are then submerged, while in the collapsed condition of the units, more than a. short distance below the water level.

The sea station upon having beentowed to its permanent location and anchored is brought into condition for permanent service by opening the sea valves 26 and by admitting water into the chambers of the supporting columns 12 and releasing the connecting columns 19 so that the latter may fill With water and submerge themselves. The ballast tanks at thelower ends of the columns are loaded with suitable ballast to facilitate this movement. When each supporting column 19 has reached its lowered position its packing 19 comes to rest against the floor plate 17a, and the bolts 19m may then be placed in position to clamp the parts together, access being afforded into the lower compartment of the buoyancy tank, for example, through the man-hole 185 (Fig. 6a).

Compressed air is now forced through pipes 31 into the chambers within the walls and bulkheads 12a, 13 of the various supporting columns until the water is partly forced out of the connecting columns 19, thereby creating a reserve buoyancy which will slightly ra1se the columns, this raising being controlled and regulated so that an apparent outside water level is established approximately at the top plates 15 of the various buoyancy tanks.

The ballast support tanks and the damping disks 26 constitute sea anchors to prevent rollingand pitching, but these anchors are the buoyancy tank:

located at such a distance below the open surface as to be in quiet water when waves of any major size are moving, but instead are subjected to the rising and falling action of the water during the movement explained above.

Under the principles enunciated above and by observation, it is found, for example, that a wave twenty feet from crest to trough is about 400 feet long; while a wave 40 feet from crest to trough is about 800 feet long. The supporting units as shown on the accompanying drawings are located at distances of 100 feet apart. Therefore, as shown in the dotted line in Fig. 2, a 400 foot wave will present its trough at one buoyancy unit A,

its mid height at the next buoyancy unit B, and its crest at the third buoyancy unit C. It will be noted that the water surface at the trough is opposite the enlarged buoyancy tank only: while that the second unit referred to comes between the column 12 and while at the third buoyancy unit, the surface of the crest of the wave comes opposite the column 12 only. Since the density of the water opposite the enlarged buoyancy tank is greater, the lifting force at the first buoyancy unit A is greater per square foot of horizontal section of this buoyancy tank than at either the second or third buoyancy tanks B or C. It will further be noted that each of the buoyancy tanks is approximately 38 feet in depth, so that the variations in water pressure at its top by reason of the increase and decrease in density as indicated by the trochoidal theory are of much greater effect than the same changes at its bottom.

As indicated in Fig. 2, for example, with a 40 foot wave which is 800 feet long, the radius of the orbital circle for a surface particle is 20 feet while the radius of a particle near the bottom of a buoyancy unit may be of the order of say 10 feet, while at the damping disk the radius of the orbital circle is only about 1 foot: and since the increase and decrease in pressure or apparent density of the water varies according to the radius of the orbital circle and the speed of movement of the water particles, it is apparent that the variations in density of water produce the desired result.

With the second buoyancy unit B in Fig. 2, the water surface is at a higher level but, since the water density is less, with a lesser lifting effort per unit of pressure area than with the first unit A, and since the pressure area is immersed to a greater distance, a greater pressure area is exposed, and the total lifting effort upon the second buoyancy unit B is substantially the same as with the first buoyancy unit A.

With the third buoyancy unit C, the pres sure area includes the whole of the exposed surface of the buoyancy tank, and also 2.

of a lesser horizontal cross section than the cross sectional area of the bouyancy tank, so that again the total lifting effort at the unit 6 is substantially identical with those of the units A and B.

It will be noted that the two positions of maximum and minimum height of wave, and hence density of water, give substantially the same lifting effort to the units so constructed and arranged: and that intermediate positions likewise are automatically compensate to give the same lifting effort. Therefore, the lifting effort exerted by each unit remains constant in spite of the presence of the 400 foot Wave passing along the length" of, or even transversely of, the sea station.

Further, with a wave 40 feet from crest to trough and 800 feet long, the buoyancy unit E has its buoyancy relatively denser water of a trough at the same instant that the preceding unit C is exposed to the mid-height of the wave and a unit A to the crest of the Wave. Here again, the greater density at the trough gives a greater lifting effort per unit of pressure area in the buoyancy tank of unit E, a lesser lifting eflort per unit of pressure area in the intermediate units D and C: while the reduced horizontal area of the column 12 assists the reduced density in compensating the lifting efforts at the units B and A so that all five units respond with a substantially identical lifting effort upon the deck structure above them.

It will be understood that as the trough of the wave travels successively from the unit A to the unit B, the crest of the wave will correspondingly travel from the unit 0 to unit D with a 400 foot wave, or from the unit E to the unit F with an 800 foot wave: and that the same identical buoyancy will continue to be exerted by each of the units upon the structure located-thereabove. Hence in ultimate efl'ect very low twisting and torsional stresses are exerted upon the deck beams 27 and their connecting members. and upon the horizontal connections 34 and the brace cables 36.

When the air is calm with very light or no winds blowing, and during sudden and abrupt changes of the wind, the sea station is practically independent of its mooring buoy 4, since the wind pressure upon the sea station becomes so low that the cable. 3 is loosened. The sea station thus might drift tank 14 exposed to the Ill toward its buoy, and become fouled with the cable 3 or with the anchor cable 4a itself.

- the yoke 53 and extends upwardly to a windlass 56 beneath the deck structure, so that the sleeve 54 may be raised and lowered. The buoy 4 itself is connected to the outer end of the cable 3, and hence by raising and lowering the tube 53, this tube may be brou ht into line with the connection of this ca le 3 to the buoy 4 itself.

The end of the towing cable is provided with an enlarged joint member 57 connecting it to the tension cable 58, this tension cable being gathered onto the Windlass drum 59 during the winding of the latter. The enlarged joint 57, when the wind pressure upon the sea station forces it away from its mooring buoy,'is brought against the inner end of the sleeve 54 so that a substantiallypositive connection is established from the mooring buoy 4 to the structure of the sea station itself, independently of the tension cable 58.

The Windlass 59 is driven through a gear train 60 by a motor 61 which is diagrammatically represented in Fig. 11' as connected to -a source of power 62 by conductors which lead through the 'limit switch 63.0perated by the towing cable 57 and tension cable 58 when the latter is wound in to near its end, thus interrupting the energization of the windlass motor 61. One of the intermediate gears 60 may, for example, be provided with a rim 64 independent of its hub 65, with springs 66 located therebetween so that while the winding effort of the Windlass is low, contacts 67 are closed for the energization of the motor 61. Thus, when there is no wind, the motor becomes energized and the tension cable 58 is drawn in until the buoy 4 is brought close up to the sleeve 54. Owing to the vertical position attained by the upper end of the anchor cable when there is no drag from the sea station upon the buoy, there is then no danger of fouling the anchor cable, while the towing cable itself has been drawn in likewise out of such danger.

It the wind then increases, the pressure upon the sea station causes a slippage of the Windlass 59 beneath its brake 68 until the limit switch 63 closes again. The motor 61 may thus take in and pay out the tension cable so long as the contacts 67 remain closed. lVhen a high wind occurs, ,with a high wind pressure and resultant pull on the mooring cable so that the latter is drawn fully out, then this action causes an opening of the contacts 67 and therewith a deenergization of the motor 61. It is intended that this automatic anchorage towing device shall operate between the limits of 5000 and 10,000 pounds towing efiort.

In order to assist in bringing the sea station into the wind, and to prevent any yawing or twisting as a result of wind pressure, an air fin is provided at the rear of the sea station, preferably beneath the deck beams where it is not in the way of the maneuvering of airplanes while alighting. At the rear end of this fin are provided a plurality of air rudders 81 which are pivotally mounted on the sea station and are provided with means whereby they may be simultaneously moved, this means being illustrated as comprising the crank arms 82 connected by the link 83 with the worm gear segment 84 which is driven by a worm gear 85 operated from the rudder motor 86 as shown in Figs. 12 and 13.

In Fig. 13 is shown a circuit diagram of the connections for the energization of the motor 86, comprising the pilot vane 87 located at a suitable part of the sea station and connected by a two to one gear 88 with the rotor 89 of an electrical movement transmitting device preferably of the selsyn type whose stator 90 is connected to the stator 91 of a differ ential selsyn incorporated in a follow-up device which has been diagrammatically illustrated as having the rotor 92 connected to the exciter 93 and mounted on a shaft 94 independent of the wormsegment 84, but having a movable contact 95 adapted to cooperate with either of the fixed contacts 96, 97 which are insulatedly mounted on the worm segment 84. The contacts 96, 97are connected by conductors 98, 99 to the coils 100 of a circuit reversing device illustrated as a. drum switch 101 connected on the one hand to a source of electric current 102 and on the other hand to the armature and field of the motor 86. A branch circuit leads to the energizing solenoid 102 of a solenoid brake 104 on the shaft of the motor 86.

In operation of this air rudder, as the pilot vane moves, being restrained against rapid vibrations by a damping device 87a, the

' selsyn windings 89, 90 and 91, 92 are operated so that the pointer 95 is ultimately brought into contact with either contact 96 or contact 97, thus energizing the motor 86 in a corresponding direction through the reversing switch 101 and causing a movement of the worm segment 84 and therewith of. the link 83 of the various air rudders 81 until the movable contact 95 is disengaged again.

During the operation of the motor 86, the so-" lenoid 102 has operated to release the solenoid brake for the free rotation of the motor. As soon as the circuit is opened through the reversing switch, the solenoid brake is' restored and holds the worm segment 84 against movement. The air rudders 81 therefore remain in their adjusted position, and thustend to stabilize the sea station against yawing; as soon as the sea station has gained a certain definite position with respect to the wind, the pilot vane 87 operates in the o posite direction, being limited in its spec of movement by the dainpener, and thus the movable contact 95 is closed with the other stationary contact and the motor 86 is operated in the opposite direction to restore the rudders 81 to a new position.

In the construction of the sea station, it is preferred to incorporate dynamometers permanently in the brace cable and in the supporting unit constructions, so that reading of these dynamometers will determine the positions of maximum efliciency to be given the various parts in calm and high seas. Since under the trochoidal theory the troughs are long and shallow while the crests are high and pointed, it is found that apparently more water is displaced'beneath the plane of maximum orbital center lines to produce the troughs than is elevated above this level to produce the crests. An apparent water level resulting from the averaging of the heights, corresponding to the plane of centers of the orbital circles of movement of the superficial water particles therefore exists which is a substantially neutral point, in which th water has neither. been reduced in pressure or apparent density by reason of its movement upward against the action of gravity, nor increased in such pressure or apparent density by its movement downward in addition to the force of gravity. It is, therefore, desired to bring the top of the buoyancy tanks to this level. ,Since this level will vary according to the radius of the orbital circles, and hence is dependent upon the height and length of the wave, it is necessary to provide means such as furnished by the air. pressure system including the pipe 30, to enable the respective units to be brought to this position. When all of the units have been brought to substantially this position the individual units can be corrected, if necessary, by the employment of the respective bilge pumps 167 to change the water ballast upon the buovancv tanks and in the connect ing columns 19. As the waves get longer and higher, the sea station is lowered slightly so that the top of the tank comes to the proper level with respect to trough and crest.

The structure is .so designed that the center of air pressure upon the stations, with a wind from abeam, is always aft of the center of water pressure. Hence, when exposed to wind of appreciable velocity, the structure as a whole will swing around into the wind and thus yawing is counteracted or prevented. This effect is accomplished by providing the necessary fin are'a80, 81 with exposure to the wind. The seadrome therefore, will always turn into a wind of appreciable velocity regardless of the efl'ect of wave ressure.

It will be understood that t e deck structure and beams, the various supporting columns and tanks, and the like, are braced internally as usual by mechanical structures to secure the necessary strength.

It is obvious that the construction and arrangement of the parts may be varied in many ways without departing from the scope of the appended claims.

Iclaim:

1. A water-supported seadrome, comprisinga superstructure and a plurality of horizontally spaced buoyancy units connected to said superstructure to support the same, each of said units having a buoyancy tank immersed in and supported by the water and a buoyant connecting column between said buoyancy tank and said superstructure of lesser horizontal cross-section than said buoyancy tank, said column being located above the water level at the trough of a wave and being in part located below the water level at the crest of a wave, so that when a unit is at the trough of a wave its buoyancy tank alone is exposed to the denserwater at the trough and when a unit is at the'crest of a wave its buoyancy tank and a part of its column are exposed to the water of lesser density at the crest of a wave, whereby the lifting efforts of individual buoyancy units 1 are equalized by the differing densities of the sectional area at its upper portion than at the lower portion, said lower portion being buoyant and immersed in and supported by the water, said upper portion being buoyant and located above the water level at the trough of a wave and being in part located below the water level at the crest of a wave,

so that when a unit is at the trough of a wave its buoyancy tank alone is exposed. to the denser water at the trough and when a unit is at the crest of a wave its buoyancy tank and a part of its column are exposed to the water of lesser density at the crest of a wave,

whereby the lifting efforts of individual buoyancy units are equalized by the difli'ering densities of the water at different parts of i the wave.

3. A water-supported seadrome, comprising a superstructure and a plurality of horizontally spaced buoyancy units connected to said superstructure to support the same, each of said units having a lesser horizontal crosssectional area at its upper portion than at the lower portion, said lower portion being buoyant and immersed in and supported by the water, said upper portion being buoyant and located above the water level at the trough of a wave and being in part located below the water level at the crest of a wave, so that when a unit is at the trough of a wave its buoyancy tank alone is exposed to the denser water at the trough and when a unit is at the crest of a wave its buoyancy tank and a part of its column are exposed to the water of lesser density at the crest of a wave, whereby the lifting efforts of individual buoyancy units are equalized by the difiering densities of the water at different parts of the wave, and means to vary the buoyancy of each said unit whereby to bring the bottom of said upper portion to the water level at the trough of the wave.

4:. A seadrome comprising a superstructure and a floating supporting assembly including a plurality of horizontally spaced buoyancy units connected to said superstructure,

each of said units having a buoyancy tankand a buoyant connecting column between said buoyancy tank and the superstructure, the buoyancy tank and column being so designed and dimensioned and so located with respect to the orbital circles of movement of the surface water of ocean waves that when a respective unit is at the trough of a wave its buoyancy tank only is exposed to the denser water at the trough and the buoyant connecting column is above the water surface, and when a unit is at the crest of a wave its buoyancy tank and a portion of its connecting column are exposed to water of lesser density, whereby the lifting efforts of individual units are equalized by the differing densities of the Water at different parts of the wave. I

5. In a seadrome, a superstructure and a plurality of horizontally spaced buoyancy units, each of said units having a buoyancy tank and a connecting column joining the tank and the superstructure, a ballast tank and a second column extending from said buoyancy tank downward to said ballast tank, said second column being collapsible within said buoyancy tank and said connecting col umn whereby to decrease the depth of draft of the seadrome when the ballast tank is raised.

6. In a seadrome, a superstructure and a plurality of horizontally spaced buoyancy units, each of said units having a buoyancy tank and a connecting column joiningthe tank and the superstructure, a damping member and a second column extending from said buoyancy tank downward to said damping member, said second column being collapsible within said buoyancy tank and said connecting column whereby to decrease the depth of draft of the seadrome when the damping member is raised.

7 In a seadrome, asuperstructure and a plurality of buoyancy units, each of said units including a buoyancy tank and a ballast tank, a hollow connecting column be- I tween the superstructure and the buoyan tank, a second column extending downwar from the buoyancy tank and connected to said ballast tank, said second column being collapsible into said hollow column, and means to limit the downward movement of said ballast tank relative to said buoyancy tank.

. damping member, said second column being collapsible into said hollow column, and means to limit the downward movement of said damping member relative to said buoyancy tank.

9. A seadrome as in claim 7 in which said second column is hollow and closed at its lower end, and a seavalve to admit water into said second column.

10. A seadrome as in claim 7, in which said second column is hollow and said hollow connecting column is closed at its upper end, and means to admit compressed air into said columns whereby to depress the water level within the columns to a point beneath the water level outside of said columns whereby to control the vertical position of said buoyancy unit.

11. In a seadrome, a superstructure and a plurality of horizontally spaced buoyancy units, each of said units comprising a buoyancy tank and a first connecting column joining the buoyancy tank to the superstructure, a ballast tank and a second connecting column joining said ballast tank to said buoyanc tank, said buoyancy tank comprising bul heads providing a water-tight chamber, and a bilge pump and piping connecting said pump to the bottom of said chamber whereby water may be withdrawn from said chamber to control the vertical position of the respective unit.

12. In a seadrome, a superstructure and a plurality of horizontally spaced buoyancy units, each of said units comprising a buoyancy tank and a first connecting column joining the buoyancy tank to the superstructure, a damping member and a second connecting column joining said damping member to said buoyancy tank, said buoyancy tank comprising bulkheads providing a water-tight chamber, and a bilge pump and piping connecting said pump to the bottom ofsaid chamber whereby water may be withdrawn from said chamber to control the vertical position of the respective unit. 7

13. In a seadrome, a superstructure and a plurality of independent buoyancy units, each of said units including a buoyancy tank, a hollow column connecting said tank to the superstructure, a damping disk and a second hollow column connecting said damping disk to said buoyancy'tank, and means to force air under pressure into all of said units whereby to depress the water level within a respective unit to a point below the water level outside of the unit, so that the superstructure may be raised as a whole.

14. In a seadrome, a superstructure and a plurality of horizontally spaced buoyancy tanks, one of said buoyancy tanks comprising a radial bulkhead and a floor, a brace cable connected to said superstructure and extending diagonally downward through the tank wall, a junction plate secured tosaid radial bulkhead and said floor and having an aperture for the end of said brace cable, and means bearing against said junction plate for engaging the cable end.

15. In a seadrome, a superstructure and a plurality of buoyancy tanks to support said superstructure, one of said buoyancy tanks having inner and outer walls and a floor, a brace cable extending from said superstructure diagonally downward through the tank wall, a junction plate secured to the floor and said inner wall, and means for attaching the lower end of the cable to said junction plate.

16. In a seadrome, a superstructure and a plurality of buoyancy tanks for supporting said superstructure, a pair of brace cables extending from said superstructure diagonally downward through the walls of a buoyancy tank, said buoyancy tank having a radial bulkhead, the cables being located on opposite sides of said bulkhead and substantially parallel thereto, and a junction plate extending on both sides of said bulkhead and connected to both of said cables.

17 In a seadrome, a superstructure and a plurality of buoyancy tanks for supporting said superstructure, one of said buoyancy tanks having outer and inner walls and radial bulkheads joined to said walls and forming a water-tight compartment within said tank, a brace cable extending from the superstructure diagonally downward through the tank Wall adjacent and parallel to one of said bulkheads, a plate secured to said bulkhead, a threaded member on the lower end of said cable, and an adjusting nut bearing against said plate and operatively engaged with said threaded member and located within the compartment, said nut being movable on said threaded member to adjust the tension of said cable.

18. In a seadrome, a superstructure and a plurality of buoyancy tanks for supporting said superstructure, one of said buoyancy tanks having outer and inner walls and radial bulkheads joined to said walls and forming water-ti ht compartments within said tank, brace cables extending from the superstructure diagonally downward through the tank walls, plates secured to the bulkheads and walls and the lower ends of said cables and adjusting means for the respective cables located within the compartments.

19. In a seadrome, a superstructure and a plurality of buoyancy tanks for supporting said superstructure, a brace cable extending from said superstructure diagonally downward and having its lower end secured inside one of said tanks, a sleeve surrounding said cable and extending above the water line'and passing through the tank walls, and means for preventing the entry of water into said sleeve.

20. In a seadrome, a superstructure and a plurality of buoyancy tanks for supporting said superstructure, one of said buoyancy tanks including a cylindrical outer wall and inner walls providing a quadrilateral vertical well in said buoyancy tank, radial bulkheads extending from said well Walls to said outer wall, pairs of brace cables extending from the superstructure diagonally downward into the tank, the cables of each pair being located on opposite sides of a radial bulkhead, and means attached to the bulkhead and said wells for securing the lower ends of the cables.

21. In a seadrome, a floating platform and a mooring buoy, anchor means to maintain said buoy, a mooring cable attached to said buoy, a guide sleeve attached to said platform and through which the mooring cable passes, and means on the platform to adjust the vertical position of said guide sleeve.

22. A mooring system as in claim 21, in which the platform includes a pair of hinge members, and a pair of spars are connected at one end of each to a hinge member and at the other end to said sleeve, and said adjusting means includes a cable connected to said sleeve to raise and lower said spars about said hinges. v

23. In a mooring system for a seadrome, a floating platform and a mooring buoy, an chor means for said buoy, a mooring cable connected to said buoy and having stop means on its other end, a sleeve mounted on said platform and surroundin said mooring cable, means to draw said mooring cable through said sleeve, and to permit it to be withdrawn through said sleeve, said sleeve engaging said stop means to determine the limit of separation of said platformfrom said buoy.

24. In a mooring system for a seadrome, a mooring cable, a tension cable secured to said mooring cable, a Windlass for winding said tension cable, a motor to drive said windlass, and a limit means operated when said mooring cable has been drawn in to a predetermined amount for deenergizing said driving motor.

25. In a seadrome mooring system, a mooring cable, a tension cable connected to said mooring cable, a Windlass to wind the said deenergize the motor upon greater than said predetermined maximum tension.

26. In a seadrome, a superstructure and buoyant supporting means therefor, a moor ing cable for the seadrome, an air rudder on said superstructure, an air vane, and means including a motor for moving said rudder controlled by the relative positions of said air rudder and said air vane to operate said rudder whereby to maintain said superstructure in a predetermined position with respect to the direction of the wind.

27. In a seadrome, a buoyancy unit including a buoyancy tank having top, bottom and peripheral walls, and an intermediate horizontal floor to divide the tank into upper and lower spaces, vertical walls to divide the upper space into a plurality of compartments, a drain conduitfrom each of said compartments into the lower space, individual valves to permit or obstruct drainage from each said compartment, and pump means to remove liquid from the said lower space.

28. In a seadrome, a buoyancy unit includ: ing a buoyancy tank having top, bottom and peripheral Walls, and an intermediate horizontal floor to divide the tank into upper and lower spaces, vertical walls to divide the upper space into a plurality of compartments and a central well, a drain conduit from each of said compartments into the lower space, individual valves to permit or obstruct drainage from each said compartment, a sea valve opening into said lower space, and air pressure means to force water from said lower space through said sea valve.

29. In a seadrome, a buoyancy unit including a buoyancy tank having top, bottom and peripheral walls, and an intermediate horizontal floor to divide the tank into upper and lower spaces, vertical walls to divide the upper space into a plurality of compartments and a central well, a drain conduit from each of said compartments into the lower. space, and individual valves to permit or obstruct drainage from each said compartment, each valve having a control handle located in said well.

30. In a seadrome, a buoyancy unit comprising a buoyancy tank, a hollow connecting column extending downward therefrom, a ballast tank at the lower end of said column, means for closing the lower end of said column, means for forcing water from said column through its lower end, and conduits for establishing communication between said column and ballast tank adjacent the top and bottom of the latter.

31. In a seadrome, a buoyancy unit comprising a buoyancy tank, a connecting column extending downward therefrom, a ballast tank at the lower end of said column, an annular member surrounding said ballast tank near its bottom, and brace means extending upwardly and inwardly fromthe outer edge of said member to said ballast tank..

32. In a seadrome, a buoyancy unit comprising a buoyancy tank, a hollow connecting column extending dowwnard therefrom, a ballast tank at the lower end of said column, a closing plate at the bottom of said column, and a sea valve to permit a controlled flow of liquid through said plate.

33. A seadrome as in claim 32, including a closing member at the upper end of said column, and valve operating means extending from said valve to above said closing member.

34. In a seadrome, a buoyancy unit comprising a buoyancy tank, a hollow connecting column extending downward therefrom and having a clamping member at its lower end, upper and lower closing members for said column providing a storage tank space within said column, a pipe leading from adjacent the lower closing member upward in said unit, and air pressure means including a conduit opening into said tank space to force liquid from said space through said pipe.

35. In a seadrome, a buoyancy unit comprising a buoyancy tank, a hollow connecting column extending downward therefrom and having a damping member at its lower end, upper and lower closing members for said column, a sea valve in said lower closing member, and means to introduce compressed air through said upper member.

36. In a seadrome, a hollow buoyancy unit comprising a buoyancy tank, a connecting column having a damping member at its lower end and adapted to telescope into said unit, and dogs on the interior of said unit to engage said column and hold it in telescoped position.

In testimony whereof I afiix my signature.

EDWARD R. ARMSTRONG. 

